Objective: 1. Arginyl-tRNA-protein transferase activity in Saccharomyces cerevisiae and Blastocladiella emersonii will be characterized with respect to determinants of donor and acceptor specificity. 2. Further studies on the physiological role of leucyl, phenylalanyl-tRNA-protein transferase in E. coli will be carried out exploiting a mutant which lacks the enzyme. 3. Attempts will be made to establish whether the eukaryotic and prokaryotic transferases perform similar physiologic functions.